Take advantage of autoresponders

Basically, once you have confirmed a potential client's willingness to
receive e-mail from you, you can enter that address into your
autoresponder program and the autoresponder will then issue preset
messages to that client on a scheduled basis. This service is used to
continue communication with the client and will hopefully generate extra
sales at some time in the future.
Depending on your business, you may make these messages ongoing
"lessons" or "updates" or basic advertisements for products you offer. The
continuing string of messages you send are entirely up to you. You make
keep adding messages for as long as there are people willing to receive
them or you can set your autoresponder to issue a set number and then not
contact that person again.
There are two types of autoresponder services you can utilize. The first is
user based and requires you to subscribe to a professional autoresponder
company. You upload them the messages you want sent and determine the
frequency. This can be done on a monthly subscription or can be based on
the number of messages sent.
Server side autoresponder programs are your own program put on your
website's server. The up side to this type of autoresponder program is that
it does not cost you more than the initial cost of the program to use it. The
downside is that you will need to gain some expertise in how to set the
program up and use it. You will need a webhosting service that supports
MySQL and Perl programming protocols and tech support that will insure
you get the script installed properly.
Once you have entered your "safelist" of e-mail addresses that have opted
into receiving your messages, you may set up the time intervals by which
the autoresponder will mail messages to them. You can set the
autoresponder to always issue the current new message or you can
program it to stagger the messages out depending on the date a new client
has signed up. That way if you are sending an informational "course" then
the new person is started with the first message and the regular routine will
send each subsequent message in its preset time and sequence.
Professional autoresponder companies have to protect their reputations by
using only the most secure autoresponders. If you are purchasing your own
autoresponder program it will be necessary to research the program you
are planning to use. Not all of them are perfect and some of the bugs
discovered in a few will generate multiple copies of the same e-mail
message or send inappropriate message return requests. Either of these
bugs can cause spam complaints against your business. There have been
some autoresponder programs that actually replicated the messages
through the address books of receiver's e-mail accounts. This "sorcerer's
apprentice" style of bug will be disastrous to your e-mail marketing
campaign.
But autoresponder driven advertising campaigns have proven themselves
to be so effective that it is vital to your overall success to use this method.
The only other option would be to send out each individual message
personally. Once you have a large mailing list the amount of time required
becomes so large as to make it unworkable.
There are different ways to build your own opt-in list.